Lifting-jack.



UNITED STATES PATENT OFFICE.

FRANK E. MODLIN, OF'SOUTH'SIOUX CITY, NEBRASKA, ASSIGNOR TO F. A. WOOD, OF

DAKOTA, NEBRASKA.

LIFTING-LTACK.

Specification of Letters Patent.

Patented July 21, 1908.

To allwhom 'it may concern.'

Beit known that I, FRANK E. MoDLIN, a citizen of the United States, and a resident of South Sioux city, in the county of Dakota and State of Nebraska, have invented certain new and useful Improvements in Liftin Jacks and I do hereby declare that the fol lowing is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in lifting jacks andthe invention consists in the matters hereinafter set forth and more particularly pointed out in the appended claims.

My improvements are herein shown as a plied .to that type of lifting jacks, commonljy known as carria le lifting jacks designed to Vlift a relatively xfight load, but may be applied to other types of acks, as for instance, track jacks, telephone pole jacks and the like.

In the drawings -Figure 1 is a side elevation of a lifting jack embodying my invention. Fig. 2 is a horizontal section, taken on line 2-2 thereof, with the operating lever swung upwardly. Fig. 3 is a front view of the jack showing the manner of mounting the operating lever and the lifting and holding dogs. Fig. 4 is a section taken on line 4-4 of Fig. 2. Fig. 5 is a transverse section taken on line 5 5 of Fig. 1.

As shown in the drawings, designates a vertical tubular standard provided with an enlarged base 11, and 12 designates a lifting bar located in and having guiding engagement with said standard and provided at its upper end with a head 13 adapted to engage beneath the load which the jack is to lift. The standard 10 may conveniently consist of a short section of pipe to which the base 11 is cast. The said standard is formed at one side to provide a vertical slot 14 and the lifting bar is provided in line with said slot with a plurality of teeth 15 which are adapted for engagement by a lifting dog 16 and a holding dog 17 mounted in a manner hereinafter described; the lifting dog bein arranged to engage with the teeth of the li ting bar and lift said bar step-by-ste and the holding dog being arranged to hol the bar in its raised osition until further raised by the action of the lifting dog on a next lower tooth of the lifting bar. A. screw 18extending through the slot ofthe standard and having screw-threaded engagement with the lifting bar constitutes `means for holding the bar from turning in the standard.

20 designates a vertically swinging operating lever which operates the lifting dog in a manner to lift the bar 12. The said operating lever is pivoted near its inner end to a collar 21 that is xed to the upper end of the tubular standard 10 in any suitablemanner. As herein shown, said collar is provided at the slotted side of the tubular standard with a laterally extending lug 22 and the operating lever is provided at its inner end with fork arms 23, 23 which fit laterally outside of said lug and are pivoted theretoV by means of a pivot pin-o`r bolt 24. The lifting dog is pivoted to the inner ends of the fork arms of the operating lever at points just inside the pivotal connection thereof with said lug 22. The said lifting do consists of a U-shaped member, the close portion 25 of which extends transversely of the lifting bar and standard and is provided with la tooth 26 adapted for engagement with the teeth 15 of the lifting bar. The parallel members 27, 27 of said U- shaped lifting dog extend at their upper ends laterally outside the fork arms 23 and are pivoted thereto by means of short pivot pins 28, 28 extending through said fork arms and said members of the lifting dog, as best shown in Fig. 2.

The locking dog 17 comprises a vertical holding memberSO provided at its lower end with a holding tooth 31 adapted for engagement with the teeth of the lifting bar, and a generally horizontal gravity arm 32 which extends forwardly therefrom for automatically holding the tooth 31 pressed toward the teeth of the lifting bar. The said holding dog is pivoted at its angle to the same pivot bolt 24 by which the operating lever is pivotally mounted, the lug 22 being formed with a vertical recess between the fork arms of the lever 2O to receive the said locking dog, and the locking dog being apertured to receive the bolt 24. The gravity arm of the locking dog extends forwardly between the fork arms 23 on the operating lever.

The collar 21 on which is formed the hinge lug 22, of the operating lever and the holding dog is preferably made of cast metal and is shrunk on the standard 10, which latter may be made of ordinary gas pipe. This arran ement provides for a very economical,

whi e at the same time a strong and durable,

construction, and the arrangement described of the lifting and holding dogs and operating lever admits of an exceedingly simple and compact construction.

In the operation-of the jack to raise the lifting bar, the operating lever 20 is swung upwardly to thereby lower the lifting dog 16 which is pressed by gravity towards the rack bar teeth. Upon engagement of said lifting dog tooth with a tooth of the lifting bar, the operating lever is swung downwardly to raise the said bar and the holding dog automatically engages with one of the teeth of the lifting bar as it passes the holding tooth of the holding dog to hold the bar in its raised position. This operation continues until the lifting bar and the load supported thereby are raised to a desired extent. When the lifting bar is to be lowered step-by-step, the operating lever is swung to a substantially horizontal position to lower the holding dog and free its tooth from lifting engagement with the lifting bar teeth after which the holding dog and lifting dog are alternately released from the teeth of the lifting bar and the bar dropped. in a step-bystep manner. It will be observed that when the operating lever is raised to the position shown in dotted lines in Fig. 4, the tooth of the lifting dog is raised into contact with the lower inclined face 35 of the holding dog, whereby said holding dog is forced away from the lifting bar teeth. If at this time the lifting dog be pulled away from the teeth of the lifting bar said bar is free to drop at once to its lowermost position.

I claim as my inventionz 1. A lifting jack comprising a tubular, slotted standard, a lifting bar therein provided with teeth arranged in line with said slot, a collar fixed to the u per end of said standard, an operating handle pivoted to the collar on the side thereof adjacent to the said slot, a lifting dog pivoted to and deending from the inner end of the operating lever exterior to the pivot of said lever and provided at its lower end with a tooth adapted for engagement with the teeth of the lifting bar, and a holding dog pivoted also to and de ending from said collar at a point above t e toothed portion of the lifting dog and adapted for engagement with said lifting bar teeth.

2. A lifting jack comprising a tubular, slotted standard, a lifting bar therein rovided with a series of teeth arranged in ine with the slot in the standard, a collar fixed to the upper end of the standard. and provided on its side thereof adjacent to the slot with a lug, an operating lever pivoted to sgaesi said lug by a horizontal pivot pin, a lifting dog pivoted to the inner end of the lever, and a holding dog above the tooth of the lifting dog pivotally mounted on the operating lever pivot bolt.

3. A lifting jack comprising a slotted tubular standard, a lifting bar therein provided in line with the slotted portion of the standard with teeth, acollar fixed to the up er end of said standard and provided with a aterally extending lug, a forked operating lever, the arms of which embrace said lug and are pivoted thereto by a horizontal pin ex tending through said arms and lug, a lifting dog pivoted to the inner ends of said fork arms and adapted for engagement with the lifting bar teeth, and a holding dog pivoted to said lug and provided with a gravity arm located between the fork arms of the operating lever.

4. A lifting bar therein provided with teeth, an operating lever provided with an inner forked end, the arms of which are ivoted to the standard, a U-shaped lifting og, the arms of which are pivoted to the inner ends of the operating lever fork arms, and pro vided in its closed or transverse portion with a tooth adapted for engagement with the lifting bar teeth, and a gravity holding dog pivoted on the standard between the fork arms of the operating lever and provided at a point above the lifting dog tooth with a tooth which engages the lifting bar teeth.

5. A lifting jack comprising a hollow, slotted standard, a lifting bar therein provided at the slotted side of the standard with a vertical series of teeth, an operating handle pivoted to the upper end of the standard, a a lifting dog pivoted to and depending from the free end of the operating handle and provided at its lower end with a tooth adapted for engagement with the lifting bar teeth, and a holding dog pivoted to said standard at a point above the tooth of the lifting dog and provided at its lower end with an inclined surface adapted to be engaged by the lifting dog, when the latter is raised, to throw the holding dog out of engagement with the lifting bar teeth, whereby if the lifting dog be at this time withdrawn from the lifting bar teeth the said lifting bar is free to drop to its lowermost position.

In testimony, that I claim the foregoing as my invention I affix my signature in the presence of two witnesses, the 17th day of January A. D. 1908.

FRANK E. MODLIN.

Witnesses:

CHAs. A. METCALF, J. A, SMITH.

lifting jack comprising a standard, a 

